Do you really need 10,000 steps a day?

Very meticulous data analysis by data science folks at Cardiogram. They test the hypothesis if 10,000 steps touted by Fitbit has any effect on resting heart rate.
They used data on steps and heart rate from their App user base. Their first cut of the analysis treated users as one aggregate and found some correlation. Recognizing groups within the data they split the data into three categories and find there is no correlation between steps taken and lowering resting heart rate.
Fitbit indeed has access to same data from its user base, you wonder why they did not do this hypothesis testing or publish the results.